$ { \left[\begin{array}{r}{4} \\ {-2} \\ {-1}\end{array}\right]+\left[\begin{array}{r}{1} \\ {-2} \\ {2}\end{array}\right] = {?} } $
Solution: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{r}{4}+{1} \\ {-2}+{-2} \\ {-1}+{2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{5} \\ {-4} \\ {1}\end{array}\right]}$